Inhibitors of store‐operated calcium channels: Imidazoles,phenothiazines, and other tricyclics

Imidazoles, such as SKF 96365, clotrimazole, and miconazole, have represented the major class of inhibitors of store‐operated calcium (SOC) channels. In HL60 cells, ATP and thapsigargin cause depletion of intracellular calcium stores, resulting in activation of SOC channels. Tricyclic phenothiazines and other tricyclics, such as amitriptyline and clozapine, were found to inhibit SOC channels of HL60 cells, with trifluoperazine being of comparable potency to the imidazoles. The effects of the imidazoles and tricyclics on intracellular calcium levels in HL60 cells were compared. In addition to inhibiting SOC channels, imidazoles, in particular, miconazole, caused a marked release of intracellular calcium, apparently from the same intracellular pool depleted by ATP and thapsigargin. The phenothiazines and the other two tricyclics caused little or no release of intracellular calcium compared to that caused by miconazole. However, these compounds did cause a significant decrease in the release of intracellular calcium elicited by subsequent addition of ATP or thapsigargin. Loperamide, which appears to selectively and positively modulate activated SOC channels, augments the elevation of intracellular calcium elicited by the imidazoles and, to a lesser extent, the tricyclics. The augmentation of calcium levels by loperamide indicated that these agents had, through release of intracellular calcium, caused activation of SOC channels. Drug Dev. Res. 47:107–117, 1999. Published 1999 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.     

Adding new life to elders’ lives

Conclusion Our experience has shown that participating in computer classes brings tangible improvements to the quality of life of older learners. While some of these benefits may derive from social interaction, many more are specific to the nature of the course. Learning to use the versatile computer does not require any particular talent, yet it allows the exercise of a wide range of skills. The achievements of our participants include a novel, poetry, short stories, family histories, and a cook book. Others have catalogued collections and undertaken voluntary administrative duties, plus much more. While there is still much to learn, we may conclude that older individuals are well able to learn to use computers, that they enjoy the experience and that the consequences may prove beneficial to a greater extent than we can yet imagine.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Loperamide: A positive modulator for store-operated calcium channels?

The depletion of inositol trisphosphate-sensitive intracellular pools of calcium causes activation of store-operated calcium (SOC) channels. Loperamide at 10–30 μM has no effect on intracellular calcium levels alone, but augments calcium levels in cultured cells when SOC channels have been activated. In HL-60 leukemic cells, the apparent positive modulatory effect of loperamide on SOC channels occurs when these channels have been activated after ATP, thapsigargin, or ionomycin-elicited depletion of calcium from intracellular storage sites. Loperamide has no effect when levels of intracellular calcium are elevated through a mechanism not involving SOC channels by using sphingosine. Loperamide caused augmentation of intracellular calcium levels after activation of SOC channels in NIH 3T3 fibroblasts, astrocytoma 1321N cells, smooth muscle DDT-MF2 cells, RBL-2H3 mast cells, and pituitary GH₄C₁ cells. Only in astrocytoma cells did loperamide cause an elevation in intracellular calcium in the absence of activation of SOC channels. The augmentation of intracellular calcium elicited by loperamide in cultured cells was dependent on extracellular calcium and was somewhat resistant to agents (SKF 96365, miconazole, clotrimazole, nitrendipine, and trifluoperazine) that in the absence of loperamide effectively blocked SOC channels. It appears that loperamide augments influx of calcium through activated SOC channels.     

Generic scheme for independent performance assessment in the molecular biology laboratory

BACKGROUND: A variety of proficiency testing schemes are available for specific molecular analyses, but there is an acute need for more widely accessible schemes to assess and demonstrate general competence in DNA analysis. METHODS: Fifteen laboratories, including academic, clinical, and commercial organizations, were recruited into the prototype assessment exercise. A range of test samples were provided, and participants were required to extract DNA from simple matrices, perform PCR amplification, and score the samples as positive or negative by electrophoretic analysis of the amplification products. Results were requested as both gel images and a completed results table, and the performance of each laboratory was then scored on the submitted analytical results. RESULTS: Overall, laboratories performed the analysis successfully, with participants scoring a high proportion of the samples correctly in the two rounds of the scheme. However, not all of the laboratories were able to achieve amplification for all samples, and the performance of some laboratories was not consistent in the two rounds. In addition, several analytical problems were encountered at all stages of the process, including DNA extraction, PCR amplification, and correct recording of results. CONCLUSIONS: The generic approach described here has enabled effective cross-sectoral benchmarking of laboratories from a variety of analytical sectors. The problems encountered by some participating laboratories highlight the need for quality control and checks at all stages of the process to ensure accuracy of results. A statistical analysis of the results (ANOVA) allowed meaningful comparison of the consistency and sensitivity achieved by laboratories, demonstrating that an effective balance was achieved between the level of data obtained from laboratories and the time expenditure required from participants.     

Audit of performance of needle core biopsy diagnoses of screen detected breast lesions

Breast needle core biopsy (NCB) is now a standard diagnostic procedure in the triple assessment of screen detected breast lesions. Therefore, it is important to provide robust and up-to-date data on the performance of NCB in the screening setting. However, previous studies of NCB have suffered from either limitation in the number of assessed cases or included a mix of symptomatic and screen detected breast lesions. In this study, we have evaluated the performance of a large series of uniformly assessed NCBs of screen detected lesions (20001 cases) over a period of 10 years (1997-2007). Our results showed a gradual increase in the number of NCBs and an improvement of their performance over the period of the study; absolute sensitivity increased from 84.9% to 96.4% and complete sensitivity increased from 90.9% to 99.7%. There was also a gradual reduction in the number of surgical interventions after benign (B2) and negative (B1) NCB diagnoses. Our study provides data showing variance from the suggested thresholds for the measures of performance of NCB in the United Kingdom which could be used to provide updated evidence-based thresholds for assessment of performance of NCB diagnosis use in the assessment of breast cancer screen detected lesions in the UK and elsewhere.     

Prevalence of bone marrow micrometastases in esophagogastric cancer patients with and without neoadjuvant chemoradiotherapy

BACKGROUND: Bone marrow micrometastases are present in a high proportion of patients undergoing curative resection for esophagogastric cancer. The incorporation of preoperative systemic therapies into these patients' treatment is widely practiced. This study investigates the effect of neoadjuvant chemoradiotherapy (CRT) on the incidence of micrometastases and the viability of detected tumor cells. MATERIALS AND METHODS: Rib bone marrow was obtained from patients (n = 106) in three centers, who were selected for potentially curative resection. Patients received neoadjuvant CRT plus surgery (n = 55), or surgery alone (n = 51). To detect micrometastases, mononuclear cells were isolated from fresh marrow and immediately stained immunohistochemically with an anti-cytokeratin-18 antibody using the APAAP technique. Tumor cell viability was assessed by immunohistochemical staining of marrow cell cultures for cytokeratin-positive cells. RESULTS: Micrometastases were detected in fresh marrow in 42% (23/55) of patients who received neoadjuvant CRT plus surgery, and in 67% (34/51) of patients treated with surgery alone. Viable tumor cells were demonstrated in 10 of 18 marrow cultures from CRT plus surgery cases. In this patient subset, combination of results of staining fresh and cultured marrow significantly increased micromet detection to 78%. CONCLUSIONS: A significant proportion of patients with esophagogastric cancer have disseminated viable tumor cells at time of surgery, irrespective of pre-operative treatment. The use of marrow culture in parallel with fresh marrow staining may increase the detection of micrometastases. The persistence of tumor cells resistant to systemic therapy may explain why these regimens fail in a majority of patients.     

The Idealization of Thin Figures and Appearance Concerns in Middle School Children

Considerable research has been conducted on adolescent body image but much less on preadolescents, even though children as young as six have been shown to be dissatisfied with their bodies. This study investigates figure preferences in 10–12-year-olds and the presence of body dissatisfaction and social physique anxiety (SPA) commonly seen in older ages. Sixty children were recruited from a private school in Australia, who completed a self-report questionnaire. Results revealed that both genders nominated a significantly thinner ideal figure than they perceived their actual. As seen in the adult literature, gender differences were evident, with females higher in SPA. Results are discussed in relation to implications to prevention and intervention of body image concerns in children.